1. Technical Field
This invention relates generally to friction stir welding tools, and more particularly to the materials used to make such tools.
2. Related Art
Friction stir welding is a technique whereby the tip of a rotating friction stir tool is first plunged into an unwelded joint of two abutting metal members to be joined, after which the rotating tool is traversed along the joint causing the materials of the two members to be heated sufficiently to reach a plastic state causing displacement or stirring of the plastic materials across the joint interface which, upon cooling, results in a metallurgical weld of the two materials. The technique can also be used to join stacked metal members whereby the rotating tool is plunged through one of the members and part way into the other and then moved along to weld them together.
Friction stir weld tools are typically wrought and then machined to the desired shape. For example, the tools can be cast from a desired metal alloy and then subjected to machining to impart the desired shape and features to the friction stir tool. The manufacturing and finishing processes can limit the selection of materials available for use as friction stir tooling and further add to the cost and complexity of forming such tooling.